The present invention relates to a novel process for producing pasteurized raw liquid egg products.
Raw liquid whole egg product, which may be a mixture of raw and previously pasteurized or otherwise treated liquid egg product, has been used for many years to replace whole eggs. Liquid whole egg products have generally been considered to be more convenient for use, especially on a large scale. Liquid whole egg product is currently subjected to pasteurization processes to produce a pathogen-free food having a long shelf life.
In the United States pasteurization is generally conducted by applying heat to achieve a minimum temperature of 60 degrees centigrade for a period of 3.5 minutes. Other countries pasteurize foods under different standards. The objective of pasteurization of egg products is to produce a salmonellae-negative product, although growth of other microorganisms is also inhibit by this process.
Reference is made to an article by P. M. Foegeding and N. W. Stanley, "Growth and Inactivation of Microorganisms Isolated ftom Ultrapasteurized Egg" Journal of Food Science, Vol. 52, No. 5, 1987, T. 1219-1227, which indicates that there are several types of microorganisms found in raw egg products. For example, Pseudomonas sp, enterococcus sp, dB circulans, and B. cereus isolate, are among such microorganisms which may be isolated from raw liquid whole egg.
Many systems have been proposed to process raw whole egg roducts. For example, an article by, H. R. Ball, Jr. et al., "Functionality and Microbial Stability of Ultrapasteurized, Aseptically Packaged Refrigerated Whole Egg", Journal of Food Science, Vol. 52, No. 5, 1987, p. 1212-1218, describes the pasteurization of liquid whole egg followed by aseptically packaging the same. Although adequate, aseptic packaging techniques are restrictive in that only certain size and types of packages may be employed with apparatuses designed to achieve this task.
U.S. Pat. Nos. 2,565,311 and 2,936,240 describe prior art whole egg pasteurization processes in which the steps of heating, chilling, and packaging occur in that order.
U.S. Pat. No. 3,232,769 shows a method of preparing eggs and food products in which the whites and yolks of eggs are separated, cooked, and then mixed with salad ingredients and lactic acid to adjust the pa of the mixture. Packaging and sealing occur followed by heating to a Temperature of 170 degrees fahrenheit to destroy harmful agents.
U.S. Pat. Nos. 3,404,008; 3,579,631; and 4,511,589 teach processes for pasteurizing egg products which employ heat exchangers. Pasteurized egg products are packaged following the use of the apparatuses shown in these references. It has been found that heat exchangers tend to foul during such processes, although successful in pasteurizing the raw egg product.
U.S. Pat. No. 5,167,976 teaches a method of extending the shelf-life of liquid egg product by employing a two-step heating process followed by cooling and packaging.
U.S. Pat. Nos. 3,843,813 and 5,290,583 show radio frequency and electroheating techniques applied to pasteurization of liquid egg products.
U.S. Pat. No. 4,994,291 reveals a method of ultrapasteurizing liquid whole egg product employing time and temperature parameters. In this reference, liquid whole egg product is subjected to heat treatment described by an equivalent temperature method followed by aseptically packaging the liquid whole egg product. Applicant incorporates by reference U.S. Pat. No. 4,994,291 in its entirety in the present application.
Although the method for ultrapasteurization of liquid whole egg product represents a great advance in the processing of raw egg product, restrictions posed by aseptically packaging pasteurized liquid egg product still exists.
A method for processing liquid egg products which overcomes the disadvantages found in the prior art methods and apparatuses would be a notable advance in the food processing field.